Many vehicles presently include sophisticated navigation systems that can identify a route between two geographic positions. A primary function of these navigation systems is to identify a course between the vehicle's current position and a destination specified by an operator. See, for example, U.S. Pat. No. 4,796,189 (issued Jan. 3, 1989).
Although many conventional navigation systems evaluate time and distance when planning a course, they do not consider many other factors that an operator may deem important. For example, an operator may prefer a course that provides more scenery, less traffic, or avoids a dangerous intersection. Most navigation systems provide no means for an operator to modify or override the planned course. And once a navigation system identifies a course between two locations, the navigation system typically monitors the vehicle's movement for deviations from the planned course. If the navigation system detects a deviation, it typically generates an alert, re-plans the course, or both, which can be annoying to an operator that is attempting to plan an alternate course.
One example of a navigation system that does provide such a means for modifying the navigation system's route is found in U.S. Pat. No. 6,456,934 (issued Sep. 24, 2002) [hereinafter “the '934 patent”]. The '934 patent describes a system that “enables a user arbitrarily to set an alternative path.” A user of the system described in the '934 patent can “specify the final point of a detour and, hence, can arbitrarily set an alternative path.” To use the system described in the '934 patent, an operator uses an input device to enter a detour request at any given position, and a “final point” of the detour. The system then retrieves one or more alternative paths “interconnecting the current position of the vehicle and the final point of detour.” Finally, according to the operator's preference, the system links the final point of detour to the original course, or to the final destination.
Although the system described in the '934 patent overcomes some of the shortcomings of earlier navigation systems, there is nonetheless plenty of room for improvement. In particular, neither the system of the '934 patent nor any other known system provides a means for an operator to select particular features to create a custom course that conforms to the operator's travel preferences. Moreover, no known system is capable of adapting computation routines to remember and consider such custom courses for future travel.